PERTH, Australia — A cluster of orange objects spotted by a search plane was just fishing equipment and not related to the missing Malaysia Airlines jet, officials said Monday, in the latest disappointment in the three-week hunt that Australia's prime minister said will continue indefinitely.

The crew of an Australian P-3 Orion saw at least four orange objects that were more than 6 feet in size Sunday, and the pilot, Flight Lt. Russell Adams, dubbed the sighting their most promising lead in the search for Flight 370. But on Monday, Australian Maritime Safety Authority spokesman Jesse Platts said an analysis confirmed the objects "have nothing to do with the missing flight."

It's a frustrating pattern in the hunt for the Boeing 777, which vanished while flying from Kuala Lumpur to Beijing on March 8 with 239 people aboard: Search crews have repeatedly spotted multiple objects floating in the search area of the southern Indian Ocean, only for officials to later rule out links to the missing plane.

Australian Prime Minister Tony Abbott on Monday acknowledged the search was incredibly complex, but said officials were "well, well short" of any point where they would scale back the hunt.

Malaysian Prime Minister Najib Razak plans to travel to Perth on Wednesday to see the search operations firsthand.